Near field transducer (nft) including peg and disc of different materials

ABSTRACT

Devices having air bearing surfaces (ABS), the devices include a near field transducer (NFT) that includes a disc configured to convert photons incident thereon into plasmons; and a peg configured to couple plasmons coupled from the disc into an adjacent magnetic storage medium, wherein the disc includes a disc material and the peg includes a peg material, wherein the disc material is different from the peg material and wherein the disc material has a first real part of the permittivity and a peg material has a second real part of the permittivity and the second real part of the permittivity is not greater than the first real part of the permittivity.

PRIORITY

This application claims priority to U.S. Provisional Application No.62/167,321 entitled NEAR FIELD TRANSDUCERS (NFTS) AND ASSOCIATEDSTRUCTURES filed on May 28, 2015; U.S. Provisional Application No.62/167,318 entitled NEAR FIELD TRANSDUCER (NFT) INCLUDING AT LEAST ONEADHESION LAYER filed on May 28, 2015; U.S. Provisional Application No.62/221,909 entitled NEAR FIELD TRANSDUCER (NFT) DEVICES INCLUDINGRHODIUM (Rh) filed on Sep. 22, 2015; and U.S. Provisional ApplicationNo. 62/300,796 entitled DEVICES INCLUDING NEAR FIELD TRANSDUCER (NFT)filed Feb. 27, 2016, the disclosures of which are incorporated herein byreference thereto.

SUMMARY

Disclosed are devices having air bearing surfaces (ABS), the devicesinclude a near field transducer (NFT) that includes a disc configured toconvert photons incident thereon into plasmons; and a peg configured tocouple plasmons coupled from the disc into an adjacent magnetic storagemedium, wherein the disc includes a disc material and the peg includes apeg material, wherein the disc material is different from the pegmaterial and wherein the disc material has a first real part of thepermittivity and a peg material has a second real part of thepermittivity and the second real part of the permittivity is not greaterthan the first real part of the permittivity.

Also disclosed are devices having air bearing surfaces (ABS), thedevices include a near field transducer (NFT) that includes a discconfigured to convert photons incident thereon into plasmons; and a pegconfigured to couple plasmons coupled from the disc into an adjacentmagnetic storage medium, wherein the disc includes a disc material andthe peg includes a peg material, wherein the disc material is differentfrom the peg material and wherein the disc material and the peg materialare independently selected from: aluminum (Al), antimony (Sb), bismuth(Bi), chromium (Cr), cobalt (Co), copper (Cu), erbium (Er), gadolinium(Gd), gallium (Ga), gold (Au), hafnium (Hf), indium (In), iridium (Ir),iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb),osmium (Os), palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh),ruthenium (Ru), scandium (Sc), silicon (Si), silver (Ag), tantalum (Ta),tin (Sn), titanium (Ti), vanadium (V), tungsten (W), ytterbium (Yb),yttrium (Y), zirconium (Zr), or combinations thereof, with the caveatthat the disc material does not comprise gold (Au).

Also disclosed are devices having air bearing surfaces (ABS), the deviceincluding a near field transducer (NFT) that includes a disc configuredto convert photons incident thereon into plasmons; a peg configured tocouple plasmons coupled from the disc into an adjacent magnetic storagemedium, the peg having a front surface at the air bearing surface of thedevice, an opposing back surface, a top surface that extends from thefront surface to the back surface, two side surfaces that extend fromthe front surface to the back surface and a bottom surface that extendsfrom the front surface to the back surface; and an adhesion layerlocated on at least one surface of the peg, wherein the disc includes adisc material and the peg includes a peg material, wherein the discmaterial is different from the peg material and wherein the discmaterial and the peg material are independently selected from: aluminum(Al), antimony (Sb), bismuth (Bi), chromium (Cr), cobalt (Co), copper(Cu), erbium (Er), gadolinium (Gd), gallium (Ga), gold (Au), hafnium(Hf), indium (In), iridium (Ir), iron (Fe), manganese (Mn), molybdenum(Mo), nickel (Ni), niobium (Nb), osmium (Os), palladium (Pd), platinum(Pt), rhenium (Re), rhodium (Rh), ruthenium (Ru), scandium (Sc), silicon(Si), silver (Ag), tantalum (Ta), tin (Sn), titanium (Ti), vanadium (V),tungsten (W), ytterbium (Yb), yttrium (Y), zirconium (Zr), orcombinations thereof, with the caveat that the disc material does notcomprise gold (Au).

The above summary of the present disclosure is not intended to describeeach disclosed embodiment or every implementation of the presentdisclosure. The description that follows more particularly exemplifiesillustrative embodiments. In several places throughout the application,guidance is provided through lists of examples, which examples can beused in various combinations. In each instance, the recited list servesonly as a representative group and should not be interpreted as anexclusive list.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a hard drive slider and media arrangementaccording to an illustrative embodiment.

FIG. 2 is a cross-sectional view of a read/write head according to anillustrative embodiment.

FIG. 3 is a perspective view of a near-field transducer according to anillustrative embodiment.

FIG. 4 is a perspective view of a near-field transducer according to anillustrative embodiment.

FIGS. 5-16 are each diagrams showing multiple views of near-fieldtransducer arrangements according to additional illustrativeembodiments.

FIGS. 17A and 17B are graphs showing the effective of the real andimaginary parts of the permittivity of the peg material on the pegtemperature (FIG. 17A) and the cross track erasure (FIG. 17B).

FIGS. 18A-18E show diagrams including optional adhesion layers inpossible illustrative configurations.

The figures are not necessarily to scale. Like numbers used in thefigures refer to like components. However, it will be understood thatthe use of a number to refer to a component in a given figure is notintended to limit the component in another figure labeled with the samenumber.

DETAILED DESCRIPTION

The present disclosure generally relates to data storage devices thatutilize heat-assisted magnetic recording (HAMR), also referred to asenergy-assisted magnetic recording (EAMR), thermally-assisted magneticrecording (TAMR), and thermally-assisted recording (TAR). Thistechnology uses an energy source such as a laser to create a smallhotspot on a magnetic media during recording. The heat lowers magneticcoercivity at the hotspot, allowing a write transducer to changemagnetic orientation, after which the hotspot is allowed to rapidlycool. Due to the relatively high coercivity of the medium after cooling,the data is less susceptible to data errors due to thermally-induced,random fluctuation of magnetic orientation known as the paramagneticeffect.

A laser or other energy source may be directly (e.g., surface-attached)or indirectly (e.g., via optical fiber) coupled to a HAMR read/writehead. An optical path (e.g., waveguide) is integrated into theread/write head and delivers the light to a media-facing surface of theread/write head. Because the size of the desired hotspot (e.g., 50 nm orless) is smaller than half a wavelength of the laser light (e.g.,800-1550 nm), conventional optical focusers (e.g., lenses) arediffraction limited and cannot be used to focus the light to create thehotspot. Instead, a near-field transducer (NFT) is employed to directenergy out of the read/write head. The NFT may also be referred to as aplasmonic transducer, plasmonic antenna, near-field antenna, nano-disc,nano-patch, nano-rod, etc.

Generally, the NFT is formed by depositing a thin-film of material suchas gold, silver, copper, etc., near an integrated optics waveguide orsome other delivery system. When exposed to laser light that isdelivered via the waveguide, the light generates a surface plasmon fieldon the NFT. The NFT is shaped such that the surface plasmons aredirected out of a surface of the write head onto a magnetic recordingmedium.

Due to the intensity of the laser light and the small size of the NFT,the NFT and surrounding material are subject to a significant rise intemperature during writing. Over time, this can affect the integrityand/or reliability of the NFT, for example, causing it to becomemisshapen or recess. Other events, such as contact between theread/write head and recording medium, contamination, etc., may alsodegrade the operation of the NFT and nearby optical components.Degradation of the NFT will affect the effective service life of a HAMRread/write head. In view of this, methods and apparatuses describedherein are used to increase the thermal robustness of the NFT, such asat a peg that extends towards the recording media.

In reference now to FIG. 1, a block diagram shows a side view of aread/write head 102 according to an example embodiment. The read/writehead 102 may be used in a magnetic data storage device, e.g., HAMR harddisc drive. The read/write head 102 may also be referred as a slider,write head, read head, recording head, etc. The read/write head 102 iscoupled to an arm 104 by way of a suspension 106, e.g., a gimbal. Theread/write head 102 includes read/write transducers 108 at a trailingedge that are held proximate to a surface 110 of a magnetic recordingmedium 111, e.g., a magnetic disc. When the read/write head 102 islocated over surface 110 of recording medium 111, a flying height 112 ismaintained between the read/write head 102 and the surface 110 by adownward force of arm 104. This downward force is counterbalanced by anair cushion that exists between the surface 110 and an air bearingsurface (ABS) 103 (also referred to herein as a “media-facing surface”)of the read/write head 102 when the recording medium 111 is rotating.

A controller 118 is coupled to the read/write transducers 108, as wellas other components of the read/write head 102, such as heaters,sensors, etc. The controller 118 may be part of general- orspecial-purpose logic circuitry that controls the functions of a storagedevice that includes at least the read/write head 102 and recordingmedium 111. The controller 118 may include or be coupled to interfacecircuitry 119 such as preamplifiers, buffers, filters, digital-to-analogconverters, analog-to-digital converters, decoders, encoders, etc., thatfacilitate electrically coupling the logic of the controller 118 to thesignals used by the read/write head 102 and other components.

The illustrated read/write head 102 is configured as a HAMR device, andso includes additional components that form a hot spot on the recordingmedium 111 near the read/write transducer 108. These components includelaser 120 (or other energy source) and waveguide 122. The waveguide 122delivers light from the laser 120 to components near the read/writetransducers 108. These components are shown in greater detail in FIG. 2,which is a block diagram illustrating a cross-sectional view of theread/write head 102 according to an example embodiment.

As shown in FIG. 2, the waveguide 122 receives electromagnetic energy200 from the energy source, the energy being coupled to a near-fieldtransducer (NFT) 202. The NFT 202 is made of a metal (e.g., gold,silver, copper, etc.) that achieves surface plasmonic resonance inresponse to the applied energy 200. The NFT 202 shapes and transmits theenergy to create a small hotspot 204 on the surface 110 of medium 111. Amagnetic write pole 206 causes changes in magnetic flux near themedia-facing surface 103 in response to an applied current. Flux fromthe write pole 206 changes a magnetic orientation of the hotspot 204 asit moves past the write pole 206 in the downtrack direction(z-direction).

The energy 200 applied to the near-field transducer 202 to create thehotspot 204 can cause a significant temperature rise in a local regionnear the media-facing surface 103. The near-field transducer 202 mayinclude a heat sink 208 that draws away some heat, e.g., to the writepole 206 or other nearby heat-conductive component. Nonetheless, thetemperature increase near the near-field transducer 202 can besignificant, leading to degradation of the near-field transducer 202 andother components over time. As such, techniques described hereinfacilitate increasing thermal robustness of the near-field transducer.

In FIG. 3, a perspective views show details of a device 112 including aNFT. The device 112 can include two parts: a disc 300 and a heat sink302 proximate to (e.g., deposited directly on to) the disc 300. In thisexample, the outline of the disc 300 on the xz-plane (which is asubstrate-parallel plane) is enlarged relative to the heat sink 302,although they may be the same size. The heat sink 302 can include anangled surface 302 a that is located proximate to a write pole (see,e.g., write pole 206 in FIG. 2).

The disc 300 acts as a collector of optical energy from a waveguideand/or focusing element. The disc 300 achieves surface plasmon resonancein response to the optical energy and the surface plasmons are directedto the medium via a peg 300 b that extends from the disc 300. It shouldbe noted that the heat sink may also contribute to the energy transferprocess and in some such embodiments a NFT does not necessarily includea separate disc and heat sink but a single component that can act asboth. In this example, the disc 300 is configured as an elongated platewith rounded (e.g., circular) ends, also referred to as a stadium orcapsule shape. Other enlarged portion geometries may be used, includingcircular, rectangular, triangular, etc.

In FIG. 4, a perspective views show details of a device 412 according toan example embodiment. The device 412 includes a NFT 405 and a heat sink402 proximate to (e.g., deposited directly on to) the disc 400 of theNFT 405. In this example, the outline of the disc 400 on the xz-plane(which is a substrate-parallel plane) is enlarged relative to the heatsink 402, although they may be the same size. The heat sink 402 includesan angled surface 402 a that is located proximate to a write pole (see,e.g., write pole 206 in FIG. 2).

The disc 400 includes a top disc 400 a that acts as a collector ofoptical energy from a waveguide and/or focusing element. The top disc400 a achieves surface plasmon resonance in response to the opticalenergy and the surface plasmons are directed to the medium via a peg 400b that extends from top portion 400 a. In this example, the top portion400 a is configured as an elongated plate with rounded (e.g., circular)ends, also0 referred to as a stadium or capsule shape. Other enlargedportion geometries may be used, including circular, rectangular,triangular, etc.

The disc 400 also includes a bottom disc 400 c. The bottom disc 400 ccan also be referred to as a sunken disc. The term “sunken disc” refersto a base or bottom portion that extends below the peg, as shown by thebase portion 400 c in FIG. 3. This can also be described as the pegextending beyond the bottom disc 400 c. In some embodiments, such asthat depicted in FIG. 4, the bottom disc 400 c and the top disc 400 acan have the same outline shape (e.g., stadium shape) as well as a sameoutline size. In some embodiments, the bottom disc 400 c and the topdisc 400 a can have different outline shapes, different outline sizes,or combinations thereof. The peg 400 b extends beyond the bottom disc400 c. The bottom portion 400 c is disposed proximate a light deliverystructure (e.g., a waveguide core) and away from a write pole. In someembodiments, the bottom disc 400 c may likely be, but need not be, theprimary collector of optical energy.

In FIGS. 5-16, composite views show NFT configurations according toadditional embodiments. For purposes of convenience, the write pole andmedia-facing surface are assigned reference numbers 902 and 900,respectively in all of FIGS. 5-16. In each of FIGS. 5-16, view (a) is aplan view of a substrate-parallel plane of an NFT, heat sink, and writepole 902 near a media-facing surface 900, where the write pole 902 is atthe bottom. In these figures, view (b) is a plan view of just the NFT,and view (c) is a side view of an NFT, heat sink, and write pole 902near a media-facing surface 900. In each case, the size and shape,relative position and material of both the base portions and associatedpegs are chosen such that the base portions convert incident photonsinto plasmons. It should be noted herein that “base portions” can besimilar to “discs” as referred to elsewhere in this application. Theplasmon is coupled from the base portions to the pegs, the pegs couplingenergy into a magnetic storage medium.

In the embodiments of FIGS. 5-16, based portions, pegs, and heatsinksmay be made of similar, identical or distinct materials. In particularembodiments, the pegs may be made of a thermally robust materialdescribed above and the base portions and heat sinks may be made ofplasmonic materials. Also, in the embodiments shown in FIGS. 5-16 wherethe peg is embedded in a base portion, the base portions may includerecesses that expose a top side of the peg, and the peg may have athickness that is less than that of the base portion in which the peg isembedded. Any of the embodiments shown in FIGS. 5-16 may also be usedwith a waveguide (e.g., waveguide core) proximate the base portion(s),and may also include a plasmonic disc that is located on a side of thewaveguide that faces away from the base portion(s).

In FIG. 5, an NFT includes a disc-style base portion 904 and a peg 906.The peg 906 is rod-shaped and extends to a middle of the base portion904. The base portion 904 is has a circular contour/outline in thisexample, although a stadium or other topographically similar shapes mayalso be used. A heat sink 908 has a contour/outline that follows that ofthe base portion 904 (circular outline in this example, although couldbe stadium shaped when used with a stadium-shaped or othertopographically similarly shaped base portion) and extends from a majorsurface of the base portion 904 to the write pole 902. The heat sink 908has a smaller contour than the base portion 904 in this example,although the heat sink's contour may be the same size as that of thebase portion 904 in some embodiments. A lower base portion 910 mayoptionally be used. The lower base portion 910 extends from a secondmajor surface of the base portion 904 away from the heat sink 902. Anouter surface of the lower base portion 910 may be proximate a lightdelivery structure, e.g., waveguide (not shown).

In FIG. 6, an NFT includes a circular disc-shaped base portion 1004 anda peg 1006. The peg 1006 has a flared end 1006 a that extends to amiddle of the base portion 1004. The flared end 1006 a is a geometricalstructure that improves adhesion and/or thermal transport and/orplasmonic coupling between the peg 1006 and base portion 1004. A stadiumshape may instead be used for the outer contours of the base portion1004. A heat sink 1008 has a contour that follows that of the baseportion 1004 and extends from a major surface of the base portion 1004to the write pole 902. The heat sink 1008 has a smaller contour than thebase portion 1004 in this example, although its contour may be the samesize as that of the base portion 1004 in some embodiments. A lower baseportion 1010 may optionally be used similar to the lower base portion910 in the description of FIG. 5.

In FIG. 7, an NFT includes a crescent-shaped base portion 1104 and a peg1106. The base portion 1104 has a crescent shape in this example,although other shapes may be used, e.g. a stadium, rectangle or othertopographically similar shapes. The peg 1106 has a flared end 1106 athat extends towards the base portion 1104, however the peg 1106 andbase portion 1104 are not joined directly together. The flared end 1106a is a geometrical structure that improves plasmonic coupling betweenthe peg 1106 and base portion 1104. A heat sink 1108 joins the baseportion 1104, the peg 1106 the write pole 902. The heat sink 1108 has anoval shape in this example, although other shapes may be used, e.g., ashape that follows the contour of the base portion 1104 at one end.

In FIG. 8, an NFT includes a crescent-shaped base portion 1204 and a peg1206. The base portion 1204 has a crescent shape in this example,although other shapes may be used, e.g. a stadium, rectangle or othertopographically similar shapes. The peg 1206 has a flared end 1206 athat extends towards the base portion 1204. The peg 1206 and baseportion 1204 are not joined directly together. The flared end 1206 a isa geometrical structure that improves plasmonic coupling between the rod1206 and base portion 1204. A first heat sink 1208 joins the peg 1206 tothe write pole 902, and second heat sink 1209 joins the base portion1204 to the write pole 902. The heat sinks 1208, 1209 have oval andround shapes in this example, although other shapes may be used. For theshape of heat sink 1209 may follow that of the base portion 1204.

In FIG. 9, an NFT includes two crescent-shaped base portions 1304, 1305separated by a gap. The base portions 1304, 1305 have a crescent shapein this example, although other shapes may be used, e.g. a stadium,rectangle or other topographically equivalent shapes, designed toenhance the coupling of light from the waveguide (not shown) to thesurface plasmon. The peg 1306 has a flared end 1306 a that extendstowards the gap between the base portions 1304, 1305 however the peg1306 and base portions 1304, 1305 are not joined directly together. Theflared end 1306 a is a geometrical structure that improves plasmoniccoupling between the rod 1306 and base portions 1304, 1305. A first heatsink 1308 joins the peg 1306 to the write pole 902, and second heatsinks 1309, 1310 join the base portions 1304, 1305 to the write pole902. The heat sinks 1308-1310 have oval and round shapes in thisexample, although other shapes may be used. For the shape of heat sinks1309, 1310 may follow that of the respective base portions 1304, 1302.

In FIG. 10, an NFT includes two crescent-shaped base portions 1404, 1405separated by a gap. The base portions 1404, 1405 have a crescent shapein this example, although other shapes may be used, e.g. a stadium,rectangle or other topographically equivalent shapes, designed toenhance the coupling of light from the waveguide (not shown) to thesurface plasmon. The peg 1406 has a flared end 1406 a that extendstowards the gap between the base portions 1404, 1405. The peg 1406 andbase portions 1404, 1405 are not joined directly together. The flaredend 1406 a is a geometrical structure that improves plasmonic couplingbetween the rod 1406 and base portion 1404. A first heat sink 1408 joinsthe peg 1406 to the write pole 902, and second heat sink 1409 joins thebase portions 1404, 1405 to the write pole 902. The heat sinks 1408,1409 have oval and round shapes in this example, although other shapesmay be used. For the shape of heat sink 1409 may follows that of thebase portions 1404, 1405.

In FIG. 11, an NFT includes two crescent-shaped base portions 1504, 1505separated by a gap. The base portions 1504, 1505 have a crescent shapein this example, although other shapes may be used, e.g. a stadium,rectangle or other topographically equivalent shapes, designed toenhance the coupling of light from the waveguide (not shown) to thesurface plasmon. The peg 1506 has a flared end 1506 a that extendstowards the gap between the base portions 1504, 1505. The peg 1506 andbase portions 1504, 1505 are not joined directly together. The flaredend 1506 a is a geometrical structure that improves plasmonic couplingbetween the rod 1506 and base portion 1504. A first heat sink 1508 joinsthe peg 1506 to the write pole 902, and second heat sink 1509 joins thebase portions 1504, 1505 to the write pole 902. The heat sinks 1508,1509 have oval and round shapes in this example, although other shapesmay be used. For the shape of heat sink 1509 may follows that of thebase portions 1504, 1505.

In FIG. 12, an NFT includes a circular disc-shaped base portion 1604 anda peg 1606. The peg 1606 is rod-shaped and extends to a middle of thebase portion 904. The base portion 1604 is has two, concentric sections1604 a-b that are formed of different materials. The sections 1604 a-bmay be configured to improve any combination of plasmon coupling, heatsinking, adhesion, and diffusion prevention. For example, section 1604 amay be formed from a thermally robust material that adheres well to thepeg 1606, and section 1604 b may be formed from a plasmonic materialchosen for efficient plasmonic excitation and coupling. A stadium shapemay instead be used for the outer contours of the base portion 1604, aswell as the contours of the sections 1604 a-b. A heat sink 1608 has acontour that follows that of the base portion 1604 and extends from amajor surface of the inner section 1604 a of the base portion 1604 tothe write pole 902. The heat sink 1608 may be the same size as the outercontours of the base portion 1604 in some embodiments. A lower baseportion 1610 may optionally be used similar to the lower base portion910 in the description of FIG. 9. The lower base portion 1610 may coverone or both sections 1604 a-b of the base portion 1610.

In FIG. 13, an NFT includes a circular disc-shaped base portion 1704 anda peg 1706. The peg 1706 has a flared end 1706 a that extends into acenter of the base portion 1704. The flared end 1706 a is a geometricalstructure that may improve adhesion and/or thermal transport and/orplasmonic coupling between the peg 1706 and base portion 1704. The baseportion 1704 is has two, concentric sections 1704 a-b that are formed ofdifferent materials, and may be configured to improve any combination ofplasmon coupling, heat sinking, adhesion, and diffusion prevention. Astadium shape may instead be used for the outer contours of the baseportion 1704, as well as the contours of the sections 1704 a-b. A heatsink 1708 has a contour that follows that of the base portion 1704 andextends from a major surface of the inner section 1704 a of the baseportion 1704 to the write pole 902. The heat sink 1708 may be the samesize as the outer contours of the base portion 1704 in some embodiments.A lower base portion 1710 may optionally be used similar to the lowerbase portion 910 in the description of FIG. 5. The lower base portion1710 may cover one or both sections 1704 a-b of the base portion 1710.

In FIG. 14, an NFT includes multiple base portions 1803-1805 and a peg1806. The base portions include a disc 1805 (shown circular, but may bestadium-shaped) and two crescent shaped portions 1803, 1804 (showncrescent but may take other shapes) that are not directly connected toeither the disc 1805 or the peg 1806. The peg 1806 has a flared end 1806a that extends into a center of the disc-shaped base portion 1805. Aheat sink 1808 has a contour that follows that of the base portion 1805and extends from a major surface of the base portion 1804 to the writepole 902. The heat sink 1808 may be the same size as the outer contoursof the base portion 1804 in some embodiments. Optionally, one or both ofthe crescent shaped portions can be connected to the heat sink 1808. Alower base portion 1810 may optionally be used similar to the lower baseportion 910 in the description of FIG. 5. The lower base portion 1810may cover one or both sections 1804 a-b of the base portion 1810.

In FIG. 15, an NFT includes a disc-style base portion 1904 and a peg1906. The peg 1906 is rod-shaped and abuts an edge of the base portion1904. The base portion 1904 is has a circular contour in this example,although a stadium shape may also be used. A heat sink 1908 extends froma major surface of the base portion 1904 to the write pole 902 and maybe configured as described in regards to FIG. 5. A lower base portion1910 may optionally be used as described in regards to FIG. 5.

In FIG. 16, an NFT includes a disc-style base portion 2004 and a peg2006. The peg 2006 is rod-shaped and extends partially into the baseportion 2004, e.g., between the center of the base portion 2004 and anedge of the base portion 2004 that faces the recording media. The baseportion 2004 has a circular contour in this example, although a stadiumshape may also be used. A heat sink 2008 extends from a major surface ofthe base portion 2004 to the write pole 902 and may be configured as thedescription of FIG. 5. A lower base portion 2010 may optionally be usedas in the description of FIG. 5. The overlap between the peg and thebase portion as shown, e.g., in FIGS. 5, 14, and 16 may be chosen tooptimize the efficiency, areal density capability and/or reliability ofthe device.

The embodiments of FIGS. 15 and 16 (as well as others) in particular maygain advantage by having the peg made of a thermally robust material andthe disc made of a plasmonic material.

Any of the embodiments described above, or combinations of any of theembodiments above may use any combination of disclosed thermally robustmaterial for the peg and disclosed plasmonic material for the otherstructures (e.g., NFT base portions or discs). Also, combinations ofdisclosed material may be used in individual components, e.g., layers ofdifferent thermally robust materials may form the peg, layers ofplasmonic and thermally robust materials may form the peg and/or other(non-peg) parts of the NFT (e.g., the disc or one or more of amulti-layer disc), and layers of different plasmonic materials may beused to form the other (non-peg) parts of the NFT.

In some embodiments, the relationship between the optical properties ofthe peg material and disc material may be selected to ensure that thesize of the optical spot is of a desired size. The optical properties ofthe peg and disc materials can be described by their “relativepermittivity”, ε. Where ε is a material dependent, complex, opticalfrequency (ω) dependent quantity of the form ε(ω)=ε_(r)(ω)+iε_(i)(ω)that is related to the material refractive index: ωr(ω)=n(ω)2−k(ω)2,εi(ω)=2*n(ω)*k(ω). The real part of the permittivity, ε_(r)(ω),describes the electric field distribution in the material, and theimaginary part, ε_(i)(ω), describes the amount of energy lost toheating. To excite a plasmon resonance on the disc at a particularincident laser wavelength, either (1) the size and shape of the disc canbe chosen to support the resonance, and ε_(r)(ω) of the disc is lessthan zero; or (2) the ε_(r)(ω) of the material is chosen such that thegiven size and shape supports a resonance.

Configurations, including size and shape, relative position, materialsor combinations thereof in disclosed embodiments can be chosen such that(1) the disc converts incident photons into plasmons; (2) the plasmonsare coupled from the disc to the peg; (3) the peg couples energy intothe magnetic storage medium. “Disc” as used herein does not imply anyprescribed shape or configuration but instead a unit or portion of theNFT that converts energy from photons to plasmons. The disc may includeone or more than one pieces. The disc may include more than one piece,more than one material, or both.

The disc may either be in direct contact with the peg where theinterface is abutted, overlapping or stitched to the peg, is separatedfrom the peg by some distance, or the more than one piece of the peg maybe separated by some distance. The peg may be a rod like structure or itmay contain geometrical structures that improve adhesion, plasmoniccoupling, or both. The amount of overlap between the peg and the disc,if present may be chosen to advantageously affect efficiency, arealdensity capability, reliability, or any combination thereof. Excessive,undesirable heating may be prevented or minimized by heat sinking thedisc, the peg, or both using one or more heat sink units. The one ormore heat sink units may be made of the same or a different materialthan the peg, the disc or both.

In some embodiments, the imaginary part of the permittivity (ε_(i)(ω) ofall materials (peg and disc for example) utilized are kept as small aspossible in order to reduce the amount of heating in the device due toplasmon resonance. In some embodiments, the imaginary part of thepermittivity could be higher if the thermal, mechanical, or bothstabilities were increased to at least partially offset the increase intemperature. In some embodiments the imaginary part of the permittivitycan be large so long as the absolute magnitude of the permittivity islarge, so as to reduce the total internal field and minimize heating.

In some embodiments, materials of the peg and the disc can be chosenbased at least in part, on the real part of the permittivity (ε_(r)(ω))of the materials. For the peg to be able to focus the field into themedium, the real part of the permittivity of the peg material must beapproximately equal to, or less than the real part of the permittivityof the disc at the same wavelength. In some embodiments, this impliesthat the material of the peg has a higher effective carrierconcentration than the disc. In some embodiments, the optical criteriafor the relationship between the real part of the permittivity of thepeg and the disc may be relaxed, for example if there were substantialbenefits with respect to reliability. This may be applicable, forexample in cases where a potential peg material has a relatively highmelting point, a relatively high resistance to oxidation, or both.

The impact of the real and imaginary parts of the permittivity of thepeg on the temperature of the peg, cross track erasure (which is relatedto the size of the optical spot on the magnetic media), or both can beevaluated. FIGS. 17A and 17B show the effect of the real (ε_(r)(ω)) andimaginary (ε_(i)(ω)) parts of the permittivity of the peg on the pegtemperature (FIG. 17A); and cross track erasure (FIG. 17B) assuming adisc that is made of gold (Au). From FIG. 17A, it can be seen that inthis configuration, if the peg is made of a material that has a lowereffective carrier density than gold (a real permittivity greater than−30), then the temperature of the peg increases (see temperaturegradient lines on graph) rapidly as it becomes more difficult to coupleenergy into the media and the track width becomes larger (FIG. 17B). Ifthe peg is made of a material that has a higher effective carrierdensity than gold (a real permittivity less than −30) then the pegtemperature is reduced (FIG. 17A) and it becomes easier to couple energyinto the disc and the track width becomes narrower (FIG.17B).

In some embodiments, materials for the peg, the disc, the heat sink, orany combinations thereof can include aluminum (Al), antimony (Sb),bismuth (Bi), chromium (Cr), cobalt (Co), copper (Cu), erbium (Er),gadolinium (Gd), gallium (Ga), gold (Au), hafnium (Hf), indium (In),iridium (Ir), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni),niobium (Nb), osmium (Os), palladium (Pd), platinum (Pt), rhenium (Re),rhodium (Rh), ruthenium (Ru), scandium (Sc), silicon (Si), silver (Ag),tantalum (Ta), tin (Sn), titanium (Ti), vanadium (V), tungsten (W),ytterbium (Yb), yttrium (Y), zirconium (Zr), or combinations thereof.Illustrative examples of materials for the peg, the disc, the heat sink,or any combinations thereof can include binary and/or ternary alloysincluding Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn,Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y,Zr, or combinations thereof. Illustrative examples of materials for thepeg, the disc, the heat sink, or any combinations thereof can includelanthanides, actinides, or combinations thereof including Al, Sb, Bi,Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn, Mo, Ni, Nb, Os, Pd, Pt,Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y, Zr, or combinationsthereof. Illustrative examples of materials for the peg, the disc, theheat sink, or any combinations thereof can include dispersions includingAl, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn, Mo, Ni, Nb,Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y, Zr, orcombinations thereof. Illustrative examples of materials for the peg,the disc, the heat sink, or any combinations thereof can include alloysor intermetallics based on or including Al, Sb, Bi, Cr, Co, Cu, Er, Gd,Ga, Au, Hf, In, Ir, Fe, Mn, Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si,Ag, Ta, Sn, Ti, V, W, Yb, Y, Zr, or combinations thereof. Illustrativealloys or intermetallics can include, for example binary and ternarysilicides, nitrides, and carbides. For example vanadium silicide (VSi),niobium silicide (NbSi), tantalum silicide (TaSi), titanium silicide(TiSi), palladium silicide (PdSi) for example zirconium nitride (ZrN),aluminum nitride (AlN), tantalum nitride (TaN), hafnium nitride (HfN),titanium nitride (TiN), boron nitride (BN), niobium nitride (NbN), orcombinations thereof. Illustrative carbides can include, for examplesilicon carbide (SiC), aluminum carbide (AlC), boron carbide (BC),zirconium carbide (ZrC), tungsten carbide (WC), titanium carbide (TiC)niobium carbide (NbC), or combinations thereof. Additionally dopedoxides can also be utilized. Illustrative doped oxides can includealuminum oxide (AlO), silicon oxide (SiO), titanium oxide (TiO),tantalum oxide (TaO), yttrium oxide (YO), niobium oxide (NbO), ceriumoxide (CeO), copper oxide (CuO), tin oxide (SnO), zirconium oxide (ZrO)or combinations thereof. Illustrative examples of materials for the peg,the disc, the heat sink, or any combinations thereof can includeconducting oxides, conducting nitrides or combinations thereof ofvarious stoichiometries where one part of the oxide, nitride or carbideincludes Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn, Mo,Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y, Zr,or combinations thereof. Illustrative examples of materials for the peg,the disc, the heat sink, or any combinations thereof can include a metalincluding Al, Sb, Bi, Cr, Co, Cu, Er, Gd, Ga, Au, Hf, In, Ir, Fe, Mn,Mo, Ni, Nb, Os, Pd, Pt, Re, Rh, Ru, Sc, Si, Ag, Ta, Sn, Ti, V, W, Yb, Y,Zr doped with oxide, carbide or nitride nanoparticles. Illustrativeoxide nanoparticles can include, for example, oxides of yttrium (Y),lanthanum (La), barium (Ba), strontium (Sr), erbium (Er), zirconium(Zr), hafnium (Hf), germanium (Ge), silicon (Si), calcium (Ca), aluminum(Al), magnesium (Mg), titanium (Ti), cerium (Ce), tantalum (Ta),tungsten (W), thorium (Th), or combinations thereof. Illustrativenitride nanoparticles can include, for example, nitrides of zirconium(Zr), titanium (Ti), tantalum (Ta), aluminum (Al), boron (B), niobium(Nb), silicon (Si), indium (In), iron (Fe), copper (Cu), tungsten (W),or combinations thereof. Illustrative carbide nanoparticles can include,for example carbides of silicon (Si), aluminum (Al), boron (B),zirconium (Zr), tungsten (W), titanium (Ti), niobium (Nb), orcombinations thereof. In some embodiments nanoparticles can includecombinations of oxides, nitrides, or carbides. It is to be understoodthat lists of combinations of elements are not exclusive to monoatomicbinary combinations, for example VSi is taken to include V₂Si and VSi₂,for example.

The real and imaginary permittivity of an element, alloy, or compositioncan be determined using methods such as spectroscopic ellipsometry orimplied from spectroscopic reflectivity and transmissivity measurementsof films of representative thickness. The real and imaginarypermittivity of many common materials can be garnered from scientificreports or collations thereof, in some cases a conversion between therefractive index and the permittivity must be completed (the complexpermittivity is the square of the complex refractive index ε=(n+ik)²).For example the permittivity of Au at a wavelength of 830 nm can bedetermined from the refractive index data compiled in the “Handbook ofOptical Constants of Solids” (Ed. Edward D. Palik, Academic Press 1985),the disclosure of which is incorporated herein by reference thereto,where the value given is at a wavelength of 826.6nm and the complexrefractive index is (0.188+5.39i). The complex permittivity is then(0.188+5.39i)² or (−29.0+2.0i).

TABLE 1 Refractive indices and permittivities from “Handbook of OpticalConstants of Solids” (Ed. Edward D. Palik, Academic Press 1985)Refractive Wavelength Index Permittivity Material (nm) n k RealImaginary Absolute Au 826.6 0.188 5.39 −29.0 2.0 29.1 Ni 826.6 2.53 4.47−13.6 22.6 26.4 Al 826.6 2.74 8.31 −61.5 45.5 76.6 Ag 826.6 0.145 5.5−30.2 1.6 30.3 Cu 826.6 0.26 5.26 −27.6 2.7 27.7 Ir 826.6 2.65 5.39−22.0 28.6 36.1 Rh 826.6 2.78 6.97 −40.9 38.8 56.3 Pt 826.6 2.92 5.07−17.2 29.6 34.2 Os 826.5 2.84 1.8 4.8 10.2 11.3

In some embodiments, a disc can be made of one of the illustrativematerials discussed above having a first real permittivity (ε_(r)(ω)¹)and a peg can be made of one of the illustrative materials discussedabove that has a second real permittivity ((ε_(r)(ω)²) where the secondreal permittivity ((ε_(r)(ω)²) is not greater than (or is less than orequal to) the first real permittivity (ε_(r)(ω)¹). In some embodiments,a peg can be made of a material having a real permittivity (ε_(r)(ω)²)that is not greater than (or is less than or equal to) −30 for exampleAg, Rh, Al.

In some embodiments, a disc can be made of Cu, Ag, Al, AlTi, ZrN, TiN,Ta and a peg can be made of Au, Ag, Cu, ZrN, Ta, AlTi, Pd, Pt, Ni, Co,Ir, Rh, Al, alloys thereof, or combinations thereof, with the caveatthat the disc and the peg are not made of the same material. In someembodiments, the disc does not include gold or any alloy or materialincluding gold. In some embodiments, a peg can be made of Rh, Al, Ir,Ag, Cu, Pd, Pt, alloys thereof, or combinations thereof. In someembodiments, a peg can include Rh or Ir. In some embodiments a peg caninclude Rh. In some embodiments a peg can be made of an Au, Rh, Irternary alloy or a Rh, Ir, Pd ternary alloy.

In some embodiments, materials that have a real permittivity less than−10 (at a wavelength of 830 nm) can be used as a peg material. In someembodiments, materials with either (exclusively either) low imaginarypermittivity, or very large absolute real and very large absoluteimaginary permittivity can be utilized for the peg material. In the caseof low imaginary permittivity, imaginary permittivity may be traded formechanical robustness. For example, silver has imaginary permittivity<1, indicating very low loss, but is not mechanically or thermallyrobust, nor resistant to corrosion, whereas ZrN and Ta are mechanicallyrobust and have imaginary permittivity less than 15. Materials withlarge absolute real permittivity and large imaginary permittivity mayalso be advantageous as peg materials as they suffer less from heating.Illustrative examples can include Al, Rh, NiFe, AlTi and Ir. In someembodiments, materials that are hard, mechanically robust, resistant tooxidation, have high melting temperature, large absolute permittivity,or combinations thereof may be utilized. Illustrative examples caninclude Rh and Ir.

In some embodiments, a disc can be made of one of the illustrativematerials discussed above having a first real permittivity (ε_(r)(ω)¹)and a peg can be made of one of the illustrative materials discussedabove that has a second real permittivity ((ε_(r)(ω)²) where the secondreal permittivity ((ε_(r)(ω)²) is not greater than and within 50% of thefirst real permittivity (ε_(r)(ω)¹). In some embodiments the material ofthe peg also has a relatively high thermal stability and resistance tooxidation. In some embodiments the material of the peg also has arelatively high thermal stability and resistance to oxidation, forexample Rh or Ir but not Ni

In some embodiments, a disc can be made of one of the illustrativematerials discussed above and a peg can be made of a material having arelatively high melting point. In some illustrative embodiments,materials with high melting points can include those having a meltingpoint of not less than (or even greater than or equal to) 1000° C. Insome illustrative embodiments, materials with high melting points caninclude those having a melting point of not less than (or even greaterthan or equal to) 1500° C. In some illustrative embodiments, materialswith high melting points can include those having a melting point of notless than (or even greater than or equal to) 1800° C. Illustrativematerials that are considered to have relatively high melting points caninclude, for example those in Table 2 below.

TABLE 2 Element Melting point (° C.) Element Melting point (° C.) Be1278 Pm 1080 B 2300 Sm 1072 C 3550 Gd 1311 Si 1410 Tb 1360 Sc 1539 Dy1409 Ti 1660 Ho 1470 V 1890 Er 1522 Cr 1857 Tm 1545 Mn 1244 Lu 1659 Fe1535 Hf 2227 Co 1495 Ta 2996 Ni 1453 W 3410 Y 1523 Re 3180 Zr 1852 Os3045 Nb 2408 Ir 2410 Mo 2617 Pt 1772 Tc 2172 Au 1064 Ru 2310 Th 1750 Rh1966 Cm 1340 Pd 1552 Ac 1050 Nd 1010 Pa 1600

In some embodiments, disclosed NFTs including a disc and a peg made ofdifferent materials can also include optional adhesion layers. In someembodiments, the optional adhesion layers can be adjacent one or moresurfaces of the peg. Experimental evidence has shown, with respect torhodium pegs in particular, that the rhodium often gets oxidized duringprocessing and/or formation of the peg itself. An overlying adhesionlayer would be advantageous both to maintain the peg in the desiredlocation (prevent recession via the adhesive properties of the adhesionlayer) and protect the material of the peg (e.g., rhodium) fromoxidation during further processing. In some embodiments, the adhesionlayer could entirely wrap one or more portions of the NFT or peg portionof the NFT. In some embodiments, the adhesion layer could wrap less thanthe entire NFT or peg portion.

Possible materials for an adhesion layer can be chosen based at least inpart on the ability of the material to maintain a bond with the pegmaterial, the ability of the material to maintain a bond with theadjacent material, or combinations thereof. Typically, the NFT or morespecifically the peg, is surrounded by an oxide, therefore in order todetermine the ability of a potential material to maintain a bond withthe adjacent material, the bond strength of an element (for example)with oxygen (O) can be utilized. Table 3 below shows the bond strengthto Rhodium (Rh) as an example, the bond strength to oxygen (O), theoxidation free energy and a figure of merit (FOM) based on these threeconsiderations for various elements. It should be noted thatillustrative materials for adhesion layers for use in pegs that are madeof materials other than Rh could be chosen, based at least in part, onsimilar considerations by considering the bond strength of the potentialelements to the peg material (instead of the bond strength to Rh as seenin Table 3). Generally, an element with a bond strength to Rh that is atleast the same as Rh to Rh, a bond strength to O that is at least thesame as the bond strength of Rh to O, or some combination thereof may beuseful. Higher FOMs indicate that the element may be advantageous.

TABLE 3 Bond Bond Strength to Rh Oxidation Free Strength to O Element(kJ/mol at 298°) Energy (kJ/mol) (kJ/mol at 298°) FOM Au 232 223 −1 B475 −750 809 4 Ba 259 −1050 562 1 C 580 −400 1076 6 Ce 545 790 5 Eu 238473 0 H 241 −350 430 0 La 550 798 5 O 405 498 2 P 353 589 2 Rh 235 −500405 0 Sc 444 −1100 671 3 Si 395 −800 800 4 Th 513 877 5 Ti 390 −900 6664 U 519 755 4 V 364 −800 637 3 Y 446 −1100 714 4

Based at least in part on the above considerations, useful materials foradhesion layers may include boron (B), carbon (C), cerium (Ce),lanthanum (La), phosphorus (P), scandium (Sc), silicon (Si), thorium(Th), titanium (Ti), uranium (U), vanadium (V), yttrium (Y), orcombinations thereof. In some embodiments, adhesion layers can includeyttrium (Y), carbon (C), or combinations thereof.

Disclosed adhesion layers can be located on one or more surfaces of thepeg, the disc, or both. In some embodiments, an optional adhesion layercan be located on at least one surface of the peg. In some embodiments,an adhesion layer or layers can be located on at least one or moresurfaces of the peg that are adjacent an oxide or oxide containingstructure. An example of an oxide containing structure that may be nextto the peg includes cladding layers. As such, in some embodiments, anadhesion layer or layers can be located on at least one or more surfacesof the peg that are adjacent one or more cladding layers or structures.

FIG. 18A shows an illustrative embodiment depicting a possible locationfor an optional adhesion layer. FIG. 18A includes a disc 10, which doesnot necessarily have to be oval in shape, a peg 12 and an adhesion layer15. It should also be noted that FIG. 18A illustrates the delineationbetween the rod 11 and the peg, the portion of the rod 11 which is infront of or not within the disc 10 (this construct applies to allembodiments depicted herein, whether stated or not). Stated another way,the rod 11 includes the peg 12, but the peg 12 does not include theentire rod 11, except in cases where the peg is abutted to the rod andthen the peg also includes the entire rod. The embodiment of the devicein FIG. 18A includes an adhesion layer 15 that is located around,adjacent to, or on the entire rod 11. Although not depicted in FIG. 18A,because it is a plan view, the adhesion layer 15 can also be locatedunderneath and on top of the rod 11. Stated another way, the adhesionlayer 15 in such an embodiment can cover all surfaces of the rod 11,except the air bearing surface (ABS) 9. Such an embodiment can be formedby depositing the material of the adhesion layer before the rod materialis deposited (e.g., as a seed layer for example), depositing and formingthe rod and then depositing the material of the adhesion layer on thesurfaces of the rod 11 as seen in FIG. 18A as well as on the top surfaceof the rod, before any additional cladding material is deposited aroundor on the rod. Such all-around adhesion layers may help adhere the pegto the adjacent dielectrics and can prevent or at least minimizediffusion of the peg material into the disc or disc material into thepeg.

FIG. 18B illustrates another example of a device including an optionaladhesion layer. FIG. 18B includes a disc 10, which does not necessarilyhave to be oval in shape, a peg 12 and an adhesion layer 16. Theadhesion layer 16 in this embodiment is located around, adjacent to, oron the peg 12, but no portion of the remainder of the rod. Although notdepicted in FIG. 18B, because it is a plan view, the adhesion layer 16can also be located underneath and on top of the peg 12. Stated anotherway, the adhesion layer 16 in such an embodiment can cover all surfacesof the peg 12, except the air bearing surface (ABS). Such an embodimentcan be formed by depositing the material of the adhesion layer beforethe peg material is deposited (e.g., as a seed layer for example),forming the peg and then depositing the material of the adhesion layerafter formation of the peg (and in some embodiments part of the disc,e.g., the bottom disc) as well as on the top surface of the peg, beforeany additional cladding material is deposited around or on the peg. Suchconfigurations may promote adhesion between the peg and the dielectricwithout disrupting the thermal pathway between the rod and disc.

FIG. 18C illustrates another example of a device including an optionaladhesion layer. FIG. 18C includes a disc 10, which does not necessarilyhave to be oval in shape, a peg 12 and an adhesion layer 17. Theadhesion layer 17 in this embodiment is only located at the air bearingsurface (ABS) of the peg, which can also be called the front of the peg12. This type of an adhesion layer can also be referred to as an ABScap. This adhesion layer could then optionally be further covered orhave deposited thereon an overcoat layer. This configuration may havethe advantage of promoting adhesion of the peg to the air bearingsurface.

FIG. 18D illustrates another example of a device including an optionaladhesion layer. FIG. 18D includes a disc 19, which although not visiblein FIG. 18D is a two layer disc including a bottom disc and a top disc.This is shown in FIG. 18E, which shows the disc 19 made up of a bottomdisc 20 and a top disc 21, delineated by the dashed line. The bottomdisc 20 has a larger footprint than does the top disc 21 and the topdisc 21 is located entirely within the footprint of the bottom disc 20.The adhesion layer 18 in this illustrated embodiment is located on theexposed outer surface of the bottom disc 20, where the top disc 21 isnot covering the bottom disc 20. The adhesion layer 18 is illustrated inthis embodiment as also covering the sides of the top disc 21. It shouldbe noted that this portion of the adhesion layer 18 is not necessary andneed not be present. Although not depicted in this embodiment, theadhesion layer may also be located underneath the bottom disc 20, e.g.,adjacent the bottom surface 22 of the bottom disc 20 (as seen in FIG.18E). It should also be noted that the illustrated adhesion layer 18 islocated adjacent the side surfaces of the peg 12. Such an adhesion layercan be formed by first depositing the material of the adhesion layer (ifit is desired to have the adhesion layer adjacent the bottom surface 22of the bottom disc 20), then depositing and forming the bottom disc,depositing the top disc and then depositing the material of the adhesionlayer 18. Adhesion layers such as these may be able to prevent or atleast minimize diffusion associated with disc materials that aren'tcompletely dense. In some alternative embodiments, an adhesion layer mayalternatively or optionally be located between the bottom disc 20 andthe top disc 19. An adhesion layer located between the two discs mayserve to limit the volume of under-dense material thereby limiting thesize of the holes that may appear upon densification.

Portions of the adhesion layer that may be functioning as a seed layeras well, e.g., will have materials deposited thereof may, but need notbe made of materials different than the remaining adhesion layermaterials. It should also be noted that any combinations of the abovediscussed adhesion layer configurations or portions thereof can also beutilized and are considered to have been disclosed herein.

It should also be noted that other structures can be combined with thedevices, configurations, structures, or combinations thereof disclosedherein. For example, gas barrier layers, overcoat layers, seed layers,or combinations thereof can be combined with various devices orstructures illustrated herein.

The present disclosure is illustrated by the following example. It is tobe understood that the particular example, assumptions, modeling, andprocedures are to be interpreted broadly in accordance with the scopeand spirit of the disclosure as set forth herein.

EXAMPLE

45 nanometer rhodium (Rh) films were deposited on the alumina surface ofa three layer structure: Si/SiOx/AlOx. The Rh film was either depositeddirectly on the three layer structure, with 5 Angstroms (Å) carbon (C)deposited before the Rh, or with 5 Å yttrium (Y) deposited before theRh. The structures so formed were either tested as deposited, afterannealing at 225° C., or after annealing at 400° C. Twenty five (25)tape tests (application of a piece of transparent adhesive tape on thestructure and subsequent removal thereof) were carried out on eachstructure. The film stress (Mpa) was also measured on each structure bymeasuring the curvature (bowing) change in the substrate due to theaddition of the metal film. Table 4 below shows the results. The resultsof the tape tests are reported as positive (adding to the count) if theRh layer stayed on the structure but was not removed when the tape wasremoved.

TABLE 4 Annealed at Annealed at Film Stress Sample As deposited 225° C.400° C. (Mpa) Rh only  0/25  0/25 0/25 −738.5 Rh on 25/25 25/25 0/25−510.1 5 Å Carbon Rh on 25/25 25/25 25/25  −570.7 5 Å Yttrium

All scientific and technical terms used herein have meanings commonlyused in the art unless otherwise specified. The definitions providedherein are to facilitate understanding of certain terms used frequentlyherein and are not meant to limit the scope of the present disclosure.

As used in this specification and the appended claims, “top” and“bottom” (or other terms like “upper” and “lower”) are utilized strictlyfor relative descriptions and do not imply any overall orientation ofthe article in which the described element is located.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” encompass embodiments having pluralreferents, unless the content clearly dictates otherwise.

As used in this specification and the appended claims, the term “or” isgenerally employed in its sense including “and/or” unless the contentclearly dictates otherwise. The term “and/or” means one or all of thelisted elements or a combination of any two or more of the listedelements.

As used herein, “have”, “having”, “include”, “including”, “comprise”,“comprising” or the like are used in their open ended sense, andgenerally mean “including, but not limited to”. It will be understoodthat “consisting essentially of”, “consisting of”, and the like aresubsumed in “comprising” and the like. For example, a conductive tracethat “comprises” silver may be a conductive trace that “consists of”silver or that “consists essentially of” silver.

As used herein, “consisting essentially of,” as it relates to acomposition, apparatus, system, method or the like, means that thecomponents of the composition, apparatus, system, method or the like arelimited to the enumerated components and any other components that donot materially affect the basic and novel characteristic(s) of thecomposition, apparatus, system, method or the like.

The words “preferred” and “preferably” refer to embodiments that mayafford certain benefits, under certain circumstances. However, otherembodiments may also be preferred, under the same or othercircumstances. Furthermore, the recitation of one or more preferredembodiments does not imply that other embodiments are not useful, and isnot intended to exclude other embodiments from the scope of thedisclosure, including the claims.

Also herein, the recitations of numerical ranges by endpoints includeall numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, 5, etc. or 10 or less includes 10, 9.4, 7.6, 5, 4.3,2.9, 1.62, 0.3, etc.). Where a range of values is “up to” a particularvalue, that value is included within the range.

Use of “first,” “second,” etc. in the description above and the claimsthat follow is not intended to necessarily indicate that the enumeratednumber of objects are present. For example, a “second” substrate ismerely intended to differentiate from another infusion device (such as a“first” substrate). Use of “first,” “second,” etc. in the descriptionabove and the claims that follow is also not necessarily intended toindicate that one comes earlier in time than the other.

Thus, embodiments of devices including a near field transducer (NFT)having a peg and disc of different materials are disclosed. Theimplementations described above and other implementations are within thescope of the following claims. One skilled in the art will appreciatethat the present disclosure can be practiced with embodiments other thanthose disclosed. The disclosed embodiments are presented for purposes ofillustration and not limitation.

What is claimed is:
 1. A device having an air bearing surface (ABS), thedevice comprising: a near field transducer (NFT) comprising: a discconfigured to convert photons incident thereon into plasmons; and a pegconfigured to couple plasmons coupled from the disc into an adjacentmagnetic storage medium, wherein the disc comprises a disc material andthe peg comprises a peg material, wherein the disc material is differentfrom the peg material and wherein the disc material has a first realpart of the permittivity and a peg material has a second real part ofthe permittivity and the second real part of the permittivity is notgreater than the first real part of the permittivity.
 2. The deviceaccording to claim 1, wherein the disc material and the peg material areindependently comprise aluminum (Al), antimony (Sb), bismuth (Bi),chromium (Cr), cobalt (Co), copper (Cu), erbium (Er), gadolinium (Gd),gallium (Ga), gold (Au), hafnium (Hf), indium (In), iridium (Ir), iron(Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb), osmium(Os), palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh),ruthenium (Ru), scandium (Sc), silicon (Si), silver (Ag), tantalum (Ta),tin (Sn), titanium (Ti), vanadium (V), tungsten (W), ytterbium (Yb),yttrium (Y), zirconium (Zr), or combinations thereof; with the caveatthat the disc does not comprise gold (Au).
 3. The device according toclaim 1, wherein the disc material comprises copper (Cu), silver (Ag),aluminum (Al), tantalum (Ta), or combinations thereof.
 4. The deviceaccording to claim 1, wherein the disc material comprises AlTi, ZrN,TiN, or combinations thereof.
 5. The device according to claim 1,wherein the peg material comprises gold (Au), silver (Ag), copper (Cu),zirconium (Zr), tantalum (Ta), palladium (Pd), platinum (Pt), nickel(Ni), cobalt (Co), iridium (Ir), rhodium (Rh), aluminum (Al), orcombinations thereof.
 6. The device according to claim 1, wherein thepeg material comprises rhodium (Rh), aluminum (Al), iridium (Ir), silver(Ag), copper (Cu), palladium (Pd), platinum (Pt), or combinationsthereof.
 7. The device according to claim 1, wherein the peg materialcomprises rhodium (Rh), iridium (Ir), or combinations thereof.
 8. Thedevice according to claim 1, wherein the peg material comprises a gold(Au), rhodium (Rh), iridium (Ir) ternary alloy, a rhodium (Rh), iridium(Ir), palldium (Pd) ternary alloy, or combinations thereof.
 9. Thedevice according to claim 1 further comprising a heat sink adjacent thedisc, the heat sink comprising aluminum (Al), antimony (Sb), bismuth(Bi), chromium (Cr), cobalt (Co), copper (Cu), erbium (Er), gadolinium(Gd), gallium (Ga), gold (Au), hafnium (Hf), indium (In), iridium (Ir),iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb),osmium (Os), palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh),ruthenium (Ru), scandium (Sc), silicon (Si), silver (Ag), tantalum (Ta),tin (Sn), titanium (Ti), vanadium (V), tungsten (W), ytterbium (Yb),yttrium (Y), zirconium (Zr), or combinations thereof.
 10. The deviceaccording to claim 1, wherein the peg has a front surface at the airbearing surface of the device, an opposing back surface, a top surfacethat extends from the front surface to the back surface, two sidesurfaces that extend from the front surface to the back surface and abottom surface that extends from the front surface to the back surface;and the device further comprises an adhesion layer located on at leastone surface of the peg.
 11. The device according to claim 10, whereinthe adhesion layer comprises boron (B), carbon (C), cerium (Ce),lanthanum (La), phosphorus (P), scandium (Sc), silicon (Si), thorium(Th), titanium (Ti), uranium (U), vanadium (V), yttrium (Y), orcombinations thereof.
 12. The device according to claim 10, wherein theadhesion layer comprises yttrium (Y), carbon (C), or combinationsthereof.
 13. A device having an air bearing surface (ABS), the devicecomprising: a near field transducer (NFT) comprising: a disc configuredto convert photons incident thereon into plasmons; and a peg configuredto couple plasmons coupled from the disc into an adjacent magneticstorage medium, wherein the disc comprises a disc material and the pegcomprises a peg material, wherein the disc material is different fromthe peg material and wherein the disc material and the peg material areindependently selected from: aluminum (Al), antimony (Sb), bismuth (Bi),chromium (Cr), cobalt (Co), copper (Cu), erbium (Er), gadolinium (Gd),gallium (Ga), gold (Au), hafnium (Hf), indium (In), iridium (Ir), iron(Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb), osmium(Os), palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh),ruthenium (Ru), scandium (Sc), silicon (Si), silver (Ag), tantalum (Ta),tin (Sn), titanium (Ti), vanadium (V), tungsten (W), ytterbium (Yb),yttrium (Y), zirconium (Zr), or combinations thereof, with the caveatthat the disc material does not comprise gold (Au).
 14. The deviceaccording to claim 13, wherein the disc material comprises copper (Cu),silver (Ag), aluminum (Al), tantalum (Ta), or combinations thereof. 15.The device according to claim 13, wherein the disc material comprisesAlTi, ZrN, TiN, or combinations thereof.
 16. The device according toclaim 13, wherein the peg material comprises rhodium (Rh), aluminum(Al), iridium (Ir), silver (Ag), copper (Cu), palladium (Pd), platinum(Pt), or combinations thereof.
 17. The device according to claim 13,wherein the peg material comprises rhodium (Rh), iridium (Ir), orcombinations thereof.
 18. A device having an air bearing surface (ABS),the device comprising: a near field transducer (NFT) comprising: a discconfigured to convert photons incident thereon into plasmons; a pegconfigured to couple plasmons coupled from the disc into an adjacentmagnetic storage medium, the peg having a front surface at the airbearing surface of the device, an opposing back surface, a top surfacethat extends from the front surface to the back surface, two sidesurfaces that extend from the front surface to the back surface and abottom surface that extends from the front surface to the back surface;and an adhesion layer located on at least one surface of the peg,wherein the disc comprises a disc material and the peg comprises a pegmaterial, wherein the disc material is different from the peg materialand wherein the disc material and the peg material are independentlyselected from: aluminum (Al), antimony (Sb), bismuth (Bi), chromium(Cr), cobalt (Co), copper (Cu), erbium (Er), gadolinium (Gd), gallium(Ga), gold (Au), hafnium (Hf), indium (In), iridium (Ir), iron (Fe),manganese (Mn), molybdenum (Mo), nickel (Ni), niobium (Nb), osmium (Os),palladium (Pd), platinum (Pt), rhenium (Re), rhodium (Rh), ruthenium(Ru), scandium (Sc), silicon (Si), silver (Ag), tantalum (Ta), tin (Sn),titanium (Ti), vanadium (V), tungsten (W), ytterbium (Yb), yttrium (Y),zirconium (Zr), or combinations thereof, with the caveat that the discmaterial does not comprise gold (Au).
 19. The device according to claim18, wherein the adhesion layer comprises yttrium (Y), carbon (C), orcombinations thereof.
 20. The device according to claim 18, wherein thedisc comprises copper (Cu), silver (Ag), aluminum (Al), tantalum (Ta),or combinations thereof and the peg material comprises rhodium (Rh),aluminum (Al), iridium (Ir), silver (Ag), copper (Cu), palladium (Pd),platinum (Pt), or combinations thereof.